Powerline communications (PLC) is a useful medium for advanced metering infrastructure (AMI). PLC allows communication signals to be sent through an already installed line, so new communication lines do not need to be added. In Europe and China, many houses are connected under one low voltage (LV)/medium voltage (MV) distribution transformer. In those countries, AMI is being implemented through low voltage lines. This means that a single base node can reside in the LV side and may serve many houses. In this case, the communication signals from the base node do not need to pass through the LV/MV distribution transformer to reach the service nodes.
However, in the United States, only a few houses are connected on the low voltage side of the LV/MV distribution transformer. As a result, if the base nodes were to be positioned on the low voltage side in the United States system, then many base nodes would be needed to cover large areas or large numbers of houses. To be cost effective and to serve as many houses as possible with a fewer base nodes, in the United States power grid, the base nodes should reside on the medium voltage side of the LV/MV distribution transformers. This means that the communication signals would have to pass through the LV/MV distribution transformers. LV/MV distribution transformers typically act as a low pass filter because they are designed to pass 50/60 Hz power signals.